package org.fastsyncer.manager.listener.mysql.common.glossary;

import org.fastsyncer.manager.listener.mysql.common.util.ToStringBuilder;

public final class Pair<T> {
	private T before;
	private T after;

	public Pair() {
	}

	public Pair(T before, T after) {
		this.before = before;
		this.after = after;
	}

	public String toString() {
		return new ToStringBuilder(this)
		.append("before", before)
		.append("after", after).toString();
	}

	public T getBefore() {
		return before;
	}

	public void setBefore(T before) {
		this.before = before;
	}

	public T getAfter() {
		return after;
	}

	public void setAfter(T after) {
		this.after = after;
	}

	public void swap() {
		final T t = this.before;
		this.before = this.after;
		this.after = t;
	}

	public static void swap(Pair<?> p) {
		doSwap(p); // Nothing but capture the <?>
	}

	private static <T> void doSwap(Pair<T> p) {
		synchronized(p) {
			final T t = p.before;
			p.before = p.after;
			p.after = t;
		}
	}
}
